As shown in FIG. 7, a chain saw, generally depicted by the numeral 1, comprises a body 2 housing an internal combustion engine or the like, which drives a chain saw 3 over the peripheral edge of a guide bar 4. The guide bar 4 is formed of both right and left outer plates 5,5 and a middle plate 6 integrally joined together by copper brazing or spot welding as shown in FIG. 8 or as seen in FIG. 9 is formed of a steel plate provided on the outer peripheral end edge with a guide groove 7 in which the saw chain 3 is guided so as not to be disengaged.
Normally, the curved part 4a at the tip of the guide bar 4 is subject to most wear as it is the contact part of the guide bar 4, which has the greatest friction with the saw chain 3 due to the tension of the saw chain 3. Therefore, the wear and heat generation by the guide bar 4 and saw chain 3 at the curved tip 4a is so remarkable that the guide bar 4 and saw chain 3 are easily damaged and likely to cause a grave accident, threatening the life of the user.
Heretofore, in order to reduce the wear between the curved tip 4a and the saw chain 3 as much as possible a wear-proof member formed of a material such as "Stellite" has been welded to the guide bar 4 on the curved tip 4a at the tip.
However, when such wear-proof member is to be added to the tip of guide bar 4a, a special skill in the welding technique or the like is required, and a finishing operation as by a mechanical working or grinding is required to remove the unnecessary welded thickness, causing the welding operation to become troublesome.
An object of the present invention is to provide a method for making a chain saw guide bar wherein the work of welding a wear-proof member to the curved tip can be very easily made.
Another object of the present invention is to provide a method for making a chain saw guide bar wherein the finishing operation such as a mechanical working or grinding after the welding operation is not required, and the amount of material needed for the wear-proof member is reduced. As a result, the cost of fabricating the chain guide can be greatly reduced.